Conventionally, generation of a gait (desired gait) for causing a legged mobile robot, for example, a two-legged mobile robot to move has primarily been aimed to generate a gait (walking gait) which causes the robot to perform a smooth walking action. However, in recent years, as the development of the legged mobile robot has been advanced, it is desired to generate a gait that can cause the robot not only to walk but also run.
Note that, since the word “gait” in Chinese characters includes a Chinese character meaning “walk”, the word tends to be misunderstood as meaning only walking. However, originally, the word “gait” has a concept that also includes “running” as evidenced by the fact that it is used as a word for “trotting” or a running mode of a horse.
Distinguishing between running and walking in a most characteristic manner, it can be said that running is a movement mode in which a floor reaction force is 0 or substantially 0 at an instance when a supporting leg is switched, and walking is the other movement modes (in which a floor reaction force's vertical component is relatively constant).
In particular, in a running gait having a period in which all the legs of the robot float in the air, a floating leg of the robot falls by gravitation to land on the floor when shifting from a floating period to a landing period. Thus, at the instant of landing, a great impact tends to be made.
Thus, there has been desired a technique for generating a gait with the landing impact reduced as greatly as possible.
Therefore, an object of the present invention is to provide a gait generation device that can generate a running gait having a floating period with a landing impact being reduced as greatly as possible. Furthermore, another object of the present invention is to provide a gait generation device that can generate a gait for a robot for which a landing impact is further reduced and which ensures the stability of the robot.